Research On Quasi-static Test Of Shear Behavior Of Prefaricated Reinforced Concrete Masonry Shear Walls With Connecting Columns

The national construction industry "14th Five-Year Plan" proposed to promote the modernization of the construction industry,the development of high-quality assembled buildings will become an inevitable trend in the transformation and upgrading of the construction industry.Prefabricated Reinforced Concrete Masonry Shear Wall(PCM shear wall)structure as a new type of assembled building structure system,with the advantages of fast construction,easy quality control,low energy consumption,and through the industrialization of the production of components,assembled lifting technology standardization It solves the connection problem of vertical reinforcement in the traditional system,and doubly upgrades the traditional Reinforced Concrete Masonry Shear Wall(CM shear wall)system in terms of structural performance and construction mode.At present,the PCM shear wall system is still in the development stage,and the connection method,reliability and influence on the performance of the members in this system are the key to study,so that the construction and design methods can be determined to play an important role in the application of the project.In this paper,the horizontal connection method applicable to PCM shear walls is proposed using a combination of research methods such as proposed static test studies,numerical simulations and seismic design methods based on properties,and a systematic study of PCM shear walls with connecting columns is carried out.The main research works include:(1)For the structural characteristics of PCM shear walls,the construction design method applicable to the vertical joints between PCM shear wall members and the construction method of PCM shear walls with connecting columns were proposed.In order to study the seismic performance of PCM shear walls with connecting columns,13 wall specimens were designed and completed for the proposed static test,of which11 PCM shear walls were constructed by assembled non-in-situ masonry,i.e.,premasonry completed on-site lifting construction and installation;2 CM shear walls were constructed by traditional in-situ masonry,i.e.,the walls were completed at the designated placement of floor slabs or floor beams,and the damage patterns of the tests were summarized and analyzed.The similarities and differences of performance indexes were summarized and analyzed.(2)The hysteresis curves and load displacement characteristic values of the specimens were obtained by the proposed static test,and the effects of construction method,axial compressive stress ratio,section shape,horizontal reinforcement ratio,distribution of horizontal reinforcement and shear-to-span ratio on the seismic performance of the specimens were analyzed based on the test results of the proposed static test.The results show that both PCM shear walls and CM shear walls exhibit good seismic performance,and PCM shear walls have higher shear bearing capacity,higher ductility and slower stiffness degradation rate than CM shear walls under the same conditions;for PCM shear walls,the peak bearing capacity,initial stiffness and energy dissipation capacity of the specimens are significantly increased with the increase of the specimen axial compression ratio;the presence of the flange improves the initial stiffness and peak The presence of the flange improves the initial stiffness and peak load capacity of the specimen,but reduces the deformation capacity of the specimen;increasing the reinforcement rate of horizontal reinforcement can improve the crack width of the specimen after the peak.(3)The finite element model of PCM shear wall was established by using ABAQUS software,and the properties of stiffness,bearing capacity,crack distribution and damage pattern of the specimen in the model were verified under the typical damage stage of cracking,peak and ultimate states of the specimen,which were in good agreement with the test results and verified the reasonableness of parameter selection and model validity in the finite element model.On this basi s,the expanded parametric analysis of the seismic performance of PCM shear walls was carried out,and the effects of axial compressive stress ratio,section shape and horizontal reinforcement on the seismic performance of the specimens were investigated respectively.The results show that the increase of axial compressi ve stress ratio and the setting of flanges on both sides of the specimen can effectively improve the bearing capacity and initial stiffness of the specimen,but reduce the deformation capacity of the specimen at the post-peak stage;the bearing capacity and peak displacement of the specimen are improved with the increase of horizontal reinforcement reinforcement distribution rate,which improves the deformation capacity of the specimen,but has no significant effect on the initial stiffness of the specimen;the specimen adopts uniformly distributed horizontal reinforcement distribution The ductility capacity of the specimens was significantly improved by adopting uniformly distributed horizontal reinforcement.(4)A database of reinforced block shear walls was established,and the frequency distribution of design variables in the database of shear reinforced block shear walls was analyzed to assess the accuracy of the load capacity calculation equations for reinforced block shear walls in Chinese,American,Canadian and New Zealand codes.A vulnerability function for shear walls of reinforced block masonry with inter-story displacement angle and normalized shear bearing capacity as engineering d emand parameters was established.The results show that the predicted values of our code formula are conservative and discrete;the cracking load of the specimen is about 70%of the peak load;compared with the interlayer displacement angle,the normalized shear bearing capacity is a better damage indicator,and its susceptibility results are less discrete and more stable.